A&M International Faculty Member Published in Journal

Dr. Mario G. Garcia-Rios, Assistant Professor of Biology
at Texas A&M International University has become
the first faculty member in the University's history
to be published in the prestigious Proceeding of the
National Academy of Sciences (PNAS), the second most-cited
scientific journal in the world.

His research report, "Cloning of a Polycistronic
cDNA from Tomato Encoding gamma-glutamyl kinase and
gamma-glutamyl phosphate reductase," was published
recently in Volume 94 of the PNAS. Publication in
this scientific journal is highly selective. Papers
may be submitted by invitation only.

The published report details drought gene research
Dr. Garcia-Rios completed while a McKnight Fellow at
Purdue University.

For the research, Garcia-Rios cloned a gene from a
tomato for potential use in genetically engineered
drought resistant plants. He and a team of six researchers
worked for over five years to isolate the drought resistant
properties of the cloned gene.

According to Garcia-Rios, agriculture productivity
is severely limited by environmental stresses--heat,
cold, and water stress or drought. Plants have various
mechanisms to cope with such stresses, such as small
molecules known as compatible solutes.

One compatible solute is proline, an amino acid synthesized
by three enzymes, including gamma-glutamyl kinase
(GK). Because most organisms produce very little proline,
Garcia-Rios cloned the GK gene from a tomato so that
the proline-producing gene could be manipulated into
other plants.

"By manipulating the GK gene, which controls the
stingy production of proline, we hoped to genetically
engineer plants that produce lots of proline under
drought conditions. We reasoned that if proline production
was increased, the levels of tolerance to stressful
conditions would increase," explained Garcia-Rios.

The cloned fragment, which he called "tomPRO1,"
contains genetic information not only for the GK but
for another enzyme, gamma-glutamyl phosphate reductase
(GPR).

"Analysis of the DNA sequence of this clone revealed
that GK and GPR are specified by two distinct open
messages similar to those seen in bacteria. That was
astonishing because nuclear messengers in animals and
plants are almost exclusively single message DNA pieces,"
he said.

His research yielded two items of scientific importance--the
tomPRO1 clone proved to control the proline production,
and a gene with highly unusual structure was discovered.

TomPRO1, the gene Garcia-Rios cloned, has since been
genetically modified and reintroduced into tomato plants.
Researchers at Purdue University are testing the genetically
engineered tomato plants for enhanced drought tolerance.
Results obtained thus far are very encouraging.

Garcia-Rios is philosophical about his discovery of
the unusual gene.

"I was fortunate. The discovery adds to the beautiful
picture of finely-tuned genetic controls that scientists
are continuously enhancing," he said.

Garcia-Rios will continue his research towards genetically
engineering plants with enhanced drought tolerance.
Since joining A&M International in 1995, he has
cloned two tomPRO1-related DNA fragments from "solanum
spp" or "nightshade," which he explained
is "a drought tolerant cousin of the tomato."

"I hope that the sequence information provided
by these two clones will enhance our understanding
of the mechanisms that plants use to adapt to conditions
of drought stress," he added.

Last year, A&M International students enrolled
in his advanced biology courses replicated his nightshade
cloning experiments. Garcia-Rios believes they were
the first students to successfully clone a gene in
Laredo.

A native of Monterrey, Nuevo Leon, Mexico, Garcia-Rios
holds a Bachelor of Science degree in Biochemical
Engineering and a minor in Marine Biology from the
Instituto Tecnologico y de Estudios Superiores de Monterrey
(ITESM), and a Ph.D. in Molecular Genetics from Purdue
University.

Prior to beginning his graduate studies, he worked
for the Cuauhtemoc Brewery, famed for Bohemia, Tecate
and XX beverages.

He and his wife Kathleen Pletsch de Garcia, an Assistant
Professor of English and Spanish at A&M International,
have two children, Magali, 6, and Alejandra, 4.

For additional information on Dr. Garcia-Rios' research,
please contact the Office of Public Affairs at 326-2180.

University office hours are 8 a.m. - 5 p.m. Monday
- Friday.

Journalists who need additional information or help with media requests and interviews should contact the Office of Public Affairs and Information Services at pais@tamiu.edu